Application Of Genexpert Mtb/Rif Assay In The Diagnosis Of Bacteriologically-Negative Pulmonary Tuberculosis

Objective: We aimed to investigate the diagnostic performance of GeneXpert MTB/RIF assay in patients with bacteriologically-negative pulmonary tuberculosis (TB). Methods: A total of 125 suspected TB patients who underwent surgery in Beijing Chest Hospital were selected for the study and divided into the TB group (n=83, including 57 patients with bacteriologically-negative pulmonary TB) and the non-TB group (n=42) according to their clinical diagnosis results. The Ziehl-Neelsen staining, mycobacterium TB gene amplification test (TB-DNA), and GeneXpert MTB/RIF assay were performed on formalin-fixed paraffin-embedded (FFPE) tissue samples of the patients post-operatively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of these methods for the detection of mycobacterium TB (MTB) were evaluated. Results: The sensitivities of the GeneXpert MTB/RIF, TB-DNA, and acid-fast smear (AFS) tests to detect MTB in patients with pulmonary TB were 71.1%, 81.9%, and 43.4%, respectively, and the specificities were 100%, 97.6%, and 97.6%, respectively. The sensitivities of the GeneXpert MTB/RIF, TB-DNA, and AFS testing methods in detecting MTB in patients with bacteriologically-negative pulmonary TB were 61.4%, 75.44%, and 35.09%, respectively, and the specificities were 61.4%, 75.5%, and 35.1%, respectively. In the detection of resistance to rifampicin in patients with bacteriologically-negative pulmonary TB, the sensitivity and specificity of Gene-Xpert MTB/RIF were 83.33% and 94.87%, respectively. Conclusion: GeneXpert MTB/RIF assay can effectively detect MTB and rifampicin resistance in patients with bacteriologically-negative pulmonary TB, demonstrating good diagnostic value for the early identification of bacteriologically-negative pulmonary TB.